There is known a semiconductor package in which a semiconductor chip (semiconductor element) is covered (sealed) with a resin-made sealing material. The sealing material for the semiconductor package is produced by molding a resin composition, for example, with a transfer molding method. In a process of producing the resin composition, the resin composition is molded into a sheet shape by pressurizing the resin composition between a pair of rollers (for example, see patent document 1).
Each of the rollers described in the patent document 1 has an outer peripheral surface. It is considered that the outer peripheral surface of each of the rollers is constituted of a metallic material. In case of using the rollers having the outer peripheral surface constituted of the metallic material, pulverized metals are produced by friction between the resin composition and the outer peripheral surface of each of the rollers while the rollers press the resin composition. As a result, there is a problem in that the pulverized metals are mixed into the resin composition as metallic foreign substances. In a case in which the resin composition containing the pulverized metals is used as the sealing material for the semiconductor package, it is impossible to seal the semiconductor chip in a state that the semiconductor chip is reliably insulated. As a result, there is a case in which the semiconductor chip shorts out.    Patent document 1: JP 2006-297701A
It is an object of the present invention to provide a molding device and a molding method, which are capable of reliably preventing pulverized metals from being mixed into a resin composition when the resin composition is molded into a sheet shape by pressurization.
The above object is achieved by the present invention which is specified in the following (1) to (12).
(1) A molding device for molding a resin composition into a sheet shape by pressurizing the resin composition, the molding device comprising:
a pair of rollers for molding the resin composition into the sheet shape by pressurizing the resin composition between the rollers, the pair of the rollers arranged parallel to one another,
wherein at least an outer peripheral surface of each of the rollers is constituted of a ceramic material.
(2) The molding device described above (1), wherein each of the rollers has a columnar or cylindrical core portion and an outer layer provided on an outer periphery of the core portion, and the outer layer is constituted of the ceramic material.
(3) The molding device described above (2), wherein a thickness of the outer layer is in the range of 0.2 to 100 nm.
(4) The molding device described in any one of above (1) to (3), wherein the ceramic material contains an oxide ceramic.
(5) The molding device described in any one of above (1) to (4), wherein an arithmetic mean deviation of a profile Ra of the outer peripheral surface of each of the rollers defined by JIS B 0601 is in the range of 0 to 2 μm.
(6) The molding device described in any one of above (1) to (5), wherein the pair of the rollers is configured to be capable of adjusting a center distance between axes of the rollers.
(7) The molding device described in any one of above (1) to (6), wherein the molding device further comprises a cooling device for cooling the resin composition passing between the pair of the rollers.
(8) The molding device described above (7), wherein a surface temperature of the outer peripheral surface of each of the rollers is set to be equal to or less than 20° C. by the cooling device.
(9) The molding device described above in any one of above (1) to (8), wherein the molding device further has a kneading apparatus having a discharge passage, the resin composition is a kneaded composition kneaded by the kneading apparatus, and the pair of the rollers is provided at a downstream side of the discharge passage of the kneading apparatus.
(10) The molding device described above (9), wherein the kneading apparatus has a function of degassing the kneaded composition, and the kneaded composition degassed by the kneading apparatus is molded into the sheet shape by the pair of the rollers.
(11) The molding device described in any one of above (1) to (9), wherein the resin composition is used as a molding portion constituting an outer packaging of an IC package.
(12) A method for molding a resin composition into a sheet shape using a pair of rollers, the method comprising:
molding the resin composition into the sheet shape by pressurizing the resin composition between the pair of the rollers arranged parallel to one another,
wherein at least an outer peripheral surface of each of the rollers is constituted of a ceramic material.